Ultrasound enhancement of percutaneous drug absorption

ABSTRACT

A system for enhancing and improving the transcutaneous or transdermal delivery of topical chemicals or drugs. A disposable container contains a substantially sterile unit dose of an active agent adapted for a single use in a medical treatment. The unit dose is formulated to enhance transport of the active agent through mammalian skin when the active agent is applied to the skin and the skin is exposed to light and/or ultrasound defined by at least one specific parameter.

RELATED CASES

This application claims priority from co-pending provisional applicationSer. No. 60/080,566, filed Apr. 3, 1998.

FIELD OF THE INVENTION

The present invention generally relates to a system for enhancing andimproving the transcutaneous or transdermal delivery of various topicalchemicals or drugs (also referred to herein as "active agents").

BACKGROUND OF THE INVENTION

Heretofore, ultrasound has been primarily used for diagnostic purposeswith an outstanding safety record. It has also been used for dentalcare. Physical therapy uses ultrasound primarily to generate deep heatand also sometimes as an adjunct to wound healing. Some attempts havebeen made since the 1950's to use ultrasound to deliver hydrocortisoneinto joint spaces (originally for bursitis) or lidocaine (for painrelief) rather than injecting with needles. The current use ofultrasound to deliver drugs is primarily its use in physical therapy fornon-invasive treatment of certain musculoskeletal disorders. Research inrecent years has dramatically increased the understanding of ultrasoundand its effects on skin and transport of topical agents. However, thereis no consensus on how to optimally increase the flux or flow of topicalagents across the skin using ultrasound.

Although ultrasound has been used to deliver drugs very deeply intojoints, several problems exist with this technique. For example, if highfrequency ultrasound is directed toward a bone for an extended period oftime, then the energy can cause a burn. To some extent a focused beamtends to cause uneven concentration and uneven penetration, and may alsocause injuries. This is particularly true with older ultrasoundequipment, but is also true of many current ultrasound technology inclinical use today. An additional problem with some earlier ultrasoundequipment is that a two to four hour exposure period may be required.The newer ultrasounds use frequencies that provide results in a five totwenty minute time frame.

The use of ultrasound to deliver agents transcutaneously is generallytermed "sonophoresis" but occasionally is termed "phonophoresis".Ultrasound generally comprises high-frequency sound waves that are abovethe human hearing range (usually greater than 20,000 Hertz (Hz)frequency units).

The sound waves may be generated by applying an alternating highfrequency electrical current to a crystal such as a quartz, siliconedioxide, lithium sulfate of barium titanate. This current distorts thecrystal, creating high frequency vibrations known as the piezoelectriceffect. The sound waves produced have energy and may penetrate matter,depending on its acoustic density and composition. These sound waves maybe delivered either in a focused manner and concentrated to a focalpoint (similar to the effects achieved with a magnifying lens andsunlight) or delivered in a non focused manner, termed "collimated,"whereby the beam is uniform and parallel with no focal point (similar tofalling rain).

The depth of penetration of ultrasound is inversely related to thefrequency. Current diagnostic and therapeutic ultrasound typicallyranges in frequency from 1-3 MHZ to 4-10 MHZ. Delivery may be pulsed inbursts or continuous beam modes, either stationary or continuouslymoving (usually at a rate of about one inch per second). The energiesused generally range from a few milliwatts to a few watts.

The ultrasound energy is usually delivered through a transducer head.When used on skin, it is usually placed in direct contact with the skinusing a coupling medium (which is often an aqueous gel), as shown, forexample, in FIG. 1.

It is also known that topical agents may be applied directly to theskin.

Sometimes absorption of these agents may be enhanced by techniques suchas occlusion with synthetic materials (e.g. plastic), or transport maybe enhanced by using low level electrical means such as galvanic currentapplication or the technique of ionophoresis.

One problem with this known methodology is that of achieving moreeffective beneficial therapeutic clinical effects with topical agents byreaching higher concentrations in the dermis without damaging the dermisand/or the epidermis. Such damage may include undesirable andintolerable side effects such as flaking, peeling, persistent redness orburning.

The problem has not been adequately solved by simply using topicalagents in various vehicles at higher strength. Using solutions at higherstrength may tend to magnify the side effects. Using solutions at higherstrength may also worsen internal systemic side effects. Simply usingsolutions at higher strength tends to work too broadly, and generallyfails to selectively cause the desired effect.

Ionophoresis tends to work only if the molecules can be broken up intopositive and negative ions and then driven in. A primary disadvantage ofthis technique is that many drugs cannot be broken up into positive andnegative ions. Another disadvantage is that many drugs lose theireffectiveness if broken up in this manner.

It has been proposed that drugs may be injected into the skin using ahypodermic needle. However, a primary disadvantage of this technique isthat it generally fails to deliver the drug uniformly.

It has been proposed that drugs may be taken orally. However, in manycases this technique is not practical. For example, oral ingestion ofvitamin C generally fails to provide a sufficiently high concentrationof the drug in the skin. The technique may also involve certain risks.For example, oral ingestion of vitamin A derivatives may cause liverdamage or birth defects.

It can be seen, therefore, that while the drugs themselves may be quiteeffective if used selectively, each of the traditional routes has one ormore inherent limiting factors which prevent or inhibit the drugs fromachieving their maximum effectiveness.

SUMMARY OF THE INVENTION

In accordance with the present invention, these and other objectives maybe achieved by providing an optimal selection of ultrasound parameterssuch as frequency, intensity, pulse length, beam characteristics andapplication time on the skin (including both human and animal) toenhance the transport of topical agents into epidermal, dermal andsubcutaneous tissues. The present invention may be used to producehigher concentrations of such an agent than may be accomplished bycurrent topical application or delivery methods. Such increasedconcentrations may have beneficial effects depending on thecharacteristics of the topical agent delivered. Patients who cannottolerate current topical application methods may achieve beneficialeffects by delivering similar concentrations of the agent with little orno side effects. Topical agents which cannot normally penetrate the skinwith current methods may be transported into the dermis.

The effects of ultrasound on skin result from the release of energy.These include the non-thermal effects of (1) cavitation, (2) mechanicalstress as well as (3) thermal effects.

It appears that ultrasound exposure in the therapeutic range causescavitation in the keratinocytes of the stratum corneum as the primaryeffect in increasing skin permeability for transcutaneous transport oftopical agents (cavitation is a process where bubbles are formed whichoscillate causing structural disorder of the intercellular lipidbilayers of the keratinocytes).

In effect, this process is somewhat analogous to loosening the "mortarbetween the bricks" and expanding the "spaces between these bricks" sothat the topical agent has a transport pathway to reach the epidermisand the deeper dermis of the skin. Drug molecules that are too large topenetrate the skin at all when applied topically may achieve significantpenetration when used in conjunction with sonophoresis with properparameters. See FIG. 3 and 4.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of a preferred embodiment of the presentinvention will be made with reference to the accompanying drawings.

FIG. 1 illustrates an example of the delivery of ultrasound energythrough a coupling medium and a transducer head.

FIG. 2 illustrates an example of the percutaneous delivery of topicalagents being principally limited by the barrier function of the stratumcorneum (the outermost 15-25 microns of the skin).

FIGS. 3 and 4 illustrate an example of cavitation from ultrasound"expanding" the spaces between keratinocytes, thus creating a channelfor drugs including drug molecules that are too large to penetrate theskin when applied topically achieving significant penetration when usedin conjunction with sonophoresis with proper parameters.

FIG. 5 illustrates an example of a cross section including the stratumcorneum, the epidermis, the dermis and the subcutaneous.

FIG. 5a illustrates an example of a pretreatment of the stratum corneum.

FIG. 5b illustrates an example of a coupling agent being applied and anultrasound treatment being performed.

FIG. 5c illustrates an example of a coupling agent being removed and anactive topical agent being applied.

FIG. 5d illustrates an example of an active topical agent being removedafter an appropriate time.

FIG. 5e illustrates an example of a protective topical agent beingapplied.

FIG. 6 illustrates an example of an active topical agent which alsoserves as a coupling agent being applied, and an ultrasound treatmentbeing performed.

FIG. 7 illustrates an example of an injection of a drug or agent orautologous or donor fibroblast rich preparation.

FIG. 8 illustrates an example of an embodiment.

FIG. 9 illustrates an example of a treatment kit prepackaged to containappropriate topical agents, drugs, supplies, etc needed for a specifictreatment in accordance with the present invention.

FIG. 10 illustrates an example of a treatment regimen card that may beincluded in the kit illustrated in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description is of the best presently contemplatedmode of carrying out the invention. This description is not to be takenin a limiting sense, but is made merely for the purpose of illustratingthe general principles of the invention. The scope of the invention isbest defined by the appended claims.

In a preferred embodiment, each active agent may be specially formulatedto achieve a desired result using ultrasound. At present, many drugs areformulated to achieve a desired result using topical penetration, butthe inventor is unaware of any drug that is specially formulated toachieve a desired or optimal result using ultrasound. At present, acoupling agent must typically be used to enable effective transmissionusing ultrasound.

In a preferred embodiment each active agent may be provided in a singledose container or packet. The packet may preferably contain only a pureactive agent, at an optimal strength and/or at an optimal concentrationfor a specific use. The active agent may be dissolved in an appropriatevehicle medium, such as a gel or a liquid. All other contaminants(including, for example, preservatives, fragrances, etc.) are preferablyabsent or removed from the packet. The need to include, with the activeagent, additives for prolonging shelf life, improving stability,preventing spoilage, improving texture, etc., is thereby eliminated. Ina preferred embodiment of the invention everything is removed from theactive agent formulation which does not have a desired effect. Eachpacket is preferably packaged in a sterile manner, by radiationsterilization or other means. Additionally, the parameters of thecollimated ultrasound are preferably selected for maximum safety.Preferably, exposure times are confined to intervals of five, ten,fifteen or twenty minutes.

In this preferred embodiment a layer of the active agent may first beplaced on the skin. The ultrasound equipment may be adjusted to theoptimize the ultrasound parameters, including the exposure time, andthen turned on. The ultrasound wand may be moved gently over the skinfor the duration of the selected exposure time. The treatment isessentially complete at the end of the selected exposure time. Anyactive agent residue left on the skin may be cleansed with a gentlecleansing agent, so that no active agent is left to irritate the skin.Treatment may be repeated at periodic intervals.

In another embodiment of the invention an ultrasound gel or similarsubstance may be put on the skin first. The skin may then be exposed toultrasound. The gel may be removed and the active agent may be placed onthe skin. The active agent may be allowed to sit on the skin for aperiod of time, preferably between about five and twenty minutes. Thistends to provide a short "burst" of the active agent at a higherpenetration. The residue may then be 20 wiped off, so that no activeagent is left to irritate the skin.

Another option would be to apply the active agent in a `delivery device`such as a biomembrane, dressing or band-aid, liposome-polymer complex oraerosol spray dressing, which functions as a delivery device, but alsoprovides a barrier function. In this option, the active agent would beleft on the skin for a period of hours or perhaps overnight.

It appears that, at least in this embodiment, the increased permeabilityor barrier spreading on the cells may last for up to one or two days. Atopical agent, aerosol agent, dressing, or delivery device may beapplied to help protect during this time or to help restore the barrierfunction. A preferred formulation could be a lipid mixture such ascholesterol, ceramides, free fatty acids, linoleic acid. Another optionwould be a lipid or liposome--polymer mixture or aerosol polymercoating. Consequently, the skin may be relatively absorbent and it maybe preferable to provide some associated aftercare, such as avoidingsunburn, Retin-a or aftershave. Treatment with a topical agentspecifically formulated to "restore" or improve barrier function may beused. Such a topical agent may also be packaged as described above.

In another embodiment of the invention an outer layer of skin may beremoved before the skin is exposed to an active agent or ultrasound.This tends to enable the active agent to penetrate better and/or deeper.This may be achieved, for example, by first wiping the skin with acetoneto strip the oils out. An enzyme may then be used to selectively killonly dead skin cells. Pretreatment with heat, skin hydratingpreparations and preparations to alter (and optimize for treatment) theskin pH may also be utilized. Chemicals, abraders and lasers may also beused for this purpose, although they tend to be less discriminate. Anactive agent may then be placed on the skin and exposed to ultrasound,or the skin may be exposed to ultrasound prior to placing an activeagent on the skin. The active agent may then be wiped off. The barrierfunction of the outer skin layer tends to return within a few hours ordays.

It has been found that removing impediments to the introduction of anactive agent to the skin tends to have at least one of the followingthree effects: (1) increasing the amount of active agent which entersthe skin, (2) shortening the time during which the skin must be exposed,and/or (3) increasing the penetration depth of the active agent.Precision, uniformity and safety may be improved by reducing variationsin the material actually placed on the skin and having the ultrasoundbeam as uniformly distributed as possible.

Treatment in accordance with the present invention tends to berelatively safe, relatively inexpensive, does not necessarily need to beperformed by a physician, has a recovery time which is relatively short(and in many cases non-existent), and can be done repeatedly withvirtually no cumulative adverse effects but with cumulative beneficialeffects.

The present invention may provide a safe, effective delivery mechanismfor a wide variety of active agents, including bleaching cremes, vitaminC, the vitamin A family, and topical anesthetics. In some cases thepresent invention may allow topical anesthetics to be administered insufficient strength that scalpel work may be performed without needles.The present invention may be used for the treatment of leg ulcers, wherethe known effects of ultrasound alone may be used to stimulate woundhealing and treatment in accordance with the present invention may beused to drive one or more new agents which enhance, speed or stimulatewound healing in to greater depths, producing results that are betterand/or faster.

The packets may be provided in different sizes. For example, the size ofone packet may be configured so that there is sufficient active agent inthe packet to treat the average face. As another example,. packet sizemay be configured so that there is sufficient active agent in the packetto treat the arms and/or legs. The packet may be configured for unitdose delivery, and the active agent may be optimized both for itsvehicle and its percentage.

If two or three active agents are used in combination, or if some of theactive agents are dissolved in micro spheres or synthetic devices, thenthe penetration ratio may be affected by the coefficients of diffusionand characteristics that are unique for each active agent, includingmolecular size and shape. If two or more active agents are used incombination, then each active agent may not necessarily be driven intothe skin at the same ratio because each molecule may be driven in at adifferent rate. When several active agents are used in combination, someactive agents may be driven in to higher strengths than others based onfactors including their weight, their volume, their size, their shapeand other properties. These factors may be optimized to achieve thedesired treatment effect.

The active agent may be used to stimulate biological systems, and from adisease therapeutic standpoint the active agent may also be used toinhibit or turn off certain biological functions. In other words, thepresent invention may be used to provide an active agent concentrationof sufficient magnitude that it may cause a feedback inhibition. Forexample, if a concentration of 2% in the skin provides stimulation and aconcentration of 4% is considered optimal, then it is possible that aconcentration of 10% may provide less effect than 4% and at 15% thereverse effect may occur. It is therefore possible to have an activeagent formulation (and/or time period and/or set of parameters)optimized so that the treatment does not merely restore biologicalfunction but actually treats disease.

The embodiment illustrated in Figure IV is primarily as a`biostimulating` process and not a destructive or ablative process, suchas commonly used in today's art. Using laser therapy or ultrasound (orboth) to produce heat at a subnecrotic damage or injury threshold isanother possible embodiment. (An example might be trying to achieve adermal temperature that affects collagen perhaps beginning around 63-65°C.).

FIG. IV illustrates an example of an embodiment using low energy lasertherapy to stimulate (directly or indirectly) the production,proliferation, activation, or inhibition of the activity, structure orfunction of various biochemical or photochemical or biological processesso as to result (directly or indirectly) in effects that are beneficialto the structure, function or appearance of the skin and/or subcutaneoustissues or which results in the "rejuvenation" of photoaged,environmentally damaged or disease or drug/therapy altered skin orsubcutaneous tissue.

The present invention, in a preferred embodiment, may be used either asa pretreatment followed by topical application of a desired agent orused in a coupling media vehicle to directly deliver the desired agent.At present, topical pharmaceutical products are not generally formulatedin such a way as to optimize their efficiency as ultrasound couplants.

A preferred formulation for an "active" coupling agent is one whichwould best meet the criteria described for the optimal active agentalone, and yet would still provide an effective coupling function for anultrasound transducer head.

The present invention, in a preferred embodiment, formulates thesetopical agents in concentrations and vehicles so as to be optimallyeffective when used in conjunction with sonophoresis. Thesespecifications may vary with molecular size as well as diffusion andpartition coefficients and other factors and may be uniquely formulatedfor each agent. The preferred embodiment for many may be a gel. Alsopreferred is individual single use sterile dose packets, therebyavoiding the need for preservatives and other additives that may causeundesirable effects or side effects.

The goal in many cases may be to maximize percutaneous transmission ofthe active agent. The following principles may be useful in selectingthese formulations, except in some situations where a milder orsubmaximal effect or transmission may be desired for a given agent orsituation. In such case, the formulation may be shifted or modified tohave reduced effect. Also, certain complex or synthetic delivery systemsmay follow different principles, such as lipid bilayers (liposomes) orsynthetic polymers (microsponges).

However, for many situations the preferred formulation may be based uponthe desire to approach, but not quite reach, a saturated solution of theactive agent(s). Thus, the rate of release of active agent or drug maybe greater in vehicles in which it exhibits poorest solubility. This maybe more important than the total concentration, so as to maximizebioavailability and release.

In a preferred formulation, it may be desirable to select a vehiclewhich poorly solubilizes the active agent and which preferably mayevaporate at such a rate that the concentration of the active agentincreases to offset the release into and through the stratum corneum.However, it may also be important that it not evaporate so quickly as toprecipitate out on the skin, since this may decrease or even stoptransport (situations where stable, supersaturated solutions form may beacceptable). Thus, it may be desirable to have sufficient non-volatilevehicle to avoid precipitation from occurring during the time the activeagent may be applied to the skin. Since the transport rate may beaffected by various factors, such as those described herein, the optimalvehicle may vary not only with each specific active agent, but also withthe specific technique parameters (or disease state) since the barrierfunction (and thus transport depletion of concentration of active agentin vehicle) may vary.

Preferred ultrasound parameters may be determined in accordance withboth efficacy and safety requirements. For example, one preferred rangefor lower frequency ultrasound may be between about 25 kHz and about 3MHZ at about 0.5-2.0 W/cm² (either continuous or pulsed, using about a20-25% duty cycle if pulsed). A preferred setting within this range maybe at about 1.0 MHZ at about 2.0 W/cm², with a continuous wave beam anda treatment time of between about five and ten minutes. A preferredsetting within this range for non-continuous beam (i.e. pulsed delivery)may be at about 1.0 MHZ at about 0.2-0.5 W/cm² with a 20-25% duty cyclewith around a 2.0-20.0 msec "on" cycle and a treatment time of aboutfive and ten minutes. One preferred range for higher frequencyultrasound may be between about 3 MHZ and about 16 MHZ at about 0.2-1.0W/cm² (either continuous or pulsed, using about a 20% duty cycle ifpulses), with a treatment time of between about one and twenty minutes.A preferred setting within this range may be at about 10 MHZ at about0.2 W/cm², with a continuous treatment time of between about five andtwenty minutes.

In a preferred embodiment the beam profile may be a collimated beam withprecise control of output. In an alternative embodiment a focused beammay also be suitable. A preferred embodiment may provide a feedbackwarning if the operator loses contact with the skin, thus ensuringoptimal treatment technique.

Further adjuncts to the process which increase permeability of skin ordecrease skin barrier function may be helpful with optimizing thepresent invention. Options for this include, but are not limited to,stripping, removing, thinning or diminishing the structure, function,thickness or permeability of the stratum corneum by various mechanical,abrasive, photo acoustical, ablative, thermal, chemical, abrasive orenzymatic methods. Examples of these could include solvent or tapestripping, scrubbing, laser ablation or vaporization, chemical peeling,micro dermabrasion, enzyme peeling, or laser treatment using high peakpower, short pulse duration lasers. A preferred embodiment may be enzymepeel, which is formulated to specifically remove only the dead stratumcorneum cells.

In another embodiment of the invention sonophoresis may be used alone,without a topical agent, to produce a thermal effect (rather than todrive drugs in) to stimulate the skin (e.g. make fibroblasts, producenew collagen, elastin, etc.).

Examples of the active agent might include any of the following, eitheralone or in combination: Vitamin C; Vitamin E; Vitamin A; Vitamin K;Vitamin F; any of the various chemical forms and analogs of thesevitamins; Retin A (Tretinoin); Adapalene; Retinol; Hydroquinone; Kojicacid; various growth factors; echinacea; antibiotics; antifungals;antivirals; bleaching agents: alpha hydroxy acids; beta hydroxy acids;salicylic acid; antioxidant triad compound (with or without Tretinoin orVitamin A derivatives); seaweed and salt water derived productsantioxidants, phytoanthocyanims, phytonutrients, botanical andherbaceous products, hormones (including insulin or estrogens), enzymes,minerals, growth factors, genetically engineered substances, cofactorsor catalysts for various biological pathways and other antiagingsubstances.

The active agents used in accordance with the present invention may becharacterized by one or more of a variety of properties. Optimization ofthe active agents for use in accordance with the present invention maybe achieved by the modifying one or more of these properties. Thefollowing are examples of some of the properties which may be modified,alone or in combination, to optimize active agents for use in accordancewith the present invention:

Solubility--A sufficient concentration of active agent should preferablybe dissolved in the selected delivery system vehicle or coupling agentfor the desired treatment.

Stability--Some active agents may be unstable and may rapidly degradeafter being dissolved in a vehicle or coupling agent. Therefore, in onepreferred embodiment the active agent may be in the form of a powder(such as a freeze dried powder or lyophilized powder, for example) thatis not mixed until treatment is imminent. Other instabilities may berelated to oxidation from atmospheric oxygen or exposure to ultravioletlight or sunlight. Thus, in one preferred embodiment the active agentmay be packaged under vacuum or nitrogen or another inert gas and may bepackaged in a manner that protects the active agent from light.

Molecular Size--The active agent should preferably have a molecular sizewhich enables it to penetrate the skin at the time of maximumpermeability, and then should preferably be in a form which is either"active" or may become "activated" in the skin. For example, in the caseof Vitamin C treatments, L-ascorbic acid has stability problems but isthe active form in the skin and is a small molecule which enablespenetration. In contrast, magnesium ascorbyl phosphate is very stablebut is a much larger molecule and does not penetrate easily with currentdelivery systems. Guy & Potts have shown that the permeability of human(and mouse) stratum corneum may be determined by the molecular volume(weight) and the partition coefficient log poor.

pH--The activity of an active agent may frequently depend on anappropriate pH level. It is also important for skin to be at an optimalpH level. There is good evidence that the stratum corneum is much morepermeable to neutral molecules than the salts of the weak acids orbases. Furthermore, skin enzymes and other processes may operateoptimally at certain pH levels and poorly at others. For example, anenzyme preparation used to remove stratum corneum may operateeffectively at a pH level of 8.5. The skin may preferably be"pretreated" with a topical agent that increases the pH of the skin tothis level. At the end of the treatment it may be advantageous to addanother topical buffering solution or agent to "readjust" the skin backdown to a normal skin pH level of 5.5.

pKa--The pKa tends to affect the amount of free acid and base inequilibrium, and thus has an impact on both the beneficial and adverseclinical effects of the active agent. A recent study by the FDA hasshown that there may be considerable variation in the beneficialclinical effects (as well as the adverse and undesirable clinical sideeffects) of glycolic acid, even when the glycolic acid concentrationsare the identical percentage. For example, if the pH of the glycolicacid preparation is adjusted to around 4.4 (approximately equal to thepKa of glycolic acid), then the ratio of beneficial to adverse sideeffects is much better than when the pH is lower than the pKa (and morefree acid is available in the equilibrium). The pKa may vary fordifferent compounds and thus may effect the choice of formulation.

Purity, Sterility, Absence of Nonactive Ingredients--The presence of animpurity (including chemical contaminants, preservatives, additives,fragrances, or micro-organisms, for example) may also potentially haveenhanced penetration and thus produce undesired adverse or toxiceffects.

Lipid Bi-Layer and Ionization--These may determine the "distribution" ofthe active agent, either in the lipid phase or in the ionized chemicalform. These may affect diffusion and delivery of the active agent.

Lipophilic and Lipophobic--The choice of the delivery vehicle orcoupling agent for the active drug may be effected by these propertiesof the active agent.

Diffusion Coefficient--One of the dominant factors in determining thetransfer of the active agent into the skin, the Diffusion Coefficientmeasures the use of movement across the stratum corneum and thedifference in concentration or percentage of active agent and also thethickness of the stratum corneum.

Partition Coefficient--One of the dominant factors in determining thepercentage transfer of the active agent into the skin, the PartitionCoefficient refers to the tendency for the active agent to leave itsvehicle and enter the stratum corneum. The amount of material that movesacross the units representative of stratum corneum and a given unit oftime tends to be directly proportional to the Partition Coefficient aswell as the Diffusion Coefficient.

In a preferred embodiment the invention may be provided in the form of a"treatment kit" prepackaged to contain all the appropriate topicalagents, drugs, supplies, etc. needed for a specific treatment. The kitmay be divided into compartments or zones. Each compartment may be codedby color, number or letter (for example), so that the compartmentsfollow a "Step System" that guides the treatment provider (i.e., thenurse, esthetician, physician, etc.) through the treatment process.Within each color coded zone, individual products that are color codedto match that step color would be provided so that they would not beeasily confused.

Each kit may be produced specifically for a certain active agent. Eachkit may be produced specifically for a certain usage, based on disorderbeing treated, anatomic area, etc.

Treatment Regimen Cards may be included in the kit. The Treatment Cardsmay become a part of the patient record or chart. The Treatment Cardsmay enable the treatment provider to chart multiple, serial treatments.Such Treatment Cards may be used to record basic information such asdate of treatment, anatomic location, disorder, patient name, comments,etc. The Treatment Cards may also provide information regardingsuggested treatment intervals, numbers of treatments, incrementalincreases in treatment parameters, incremental increases in active agentapplication time or strength.

Several different Treatment Cards may be included in a kit for atreatment provider to select. For example, a single kit may includedifferent Treatment Cards for sensitive skin, regular skin, and postsurgical skin treatment. These different Treatment Cards may have, astheir distinguishing characteristics, differences in one or more of atleast the following: percentage dilution of active agents, amount oftime various agents or treatment are applied, or ultrasound or lightsource parameters, etc. Different Treatment Cards may be provided fordifferent anatomic areas, such as the face, the arms or the legs, wherethese parameters may also be varied. Different Treatment Cards may beprovided for different treatment options, for example gentle treatmentfor mild sun damage vs. aggressive treatment for severe sun damage.

The Treatment Cards may be color coded to indicate the time period forequipment parameters directly on the card. The Treatment Cards may alsocross reference for percent concentration to the kit itself (in essencewithin each step of the kit) which may be color coded (for example paleblue background).

For example, there may be three levels of dilution or strength (mild,intermediate, maximal) which may be identified by a color code on theTreatment Card.

For example, at one step of the treatment the active agent may be mixedfrom a dry powder. The mixing instructions may be imprinted on the boxfor the dilution, and the Treatment Card may also indicate therecommended dilution. For example, a patient with sensitive skinreceiving a series of six treatments may start at the most mild of thethree dilution strengths for the first three treatments and then go tothe intermediate for the last three. In contrast, a person with averageskin might have the first two treatments performed at the mild strength,the third and fourth treatments at the intermediate strength, and thefifth and sixth treatments at the maximum strength. In that case weeksone and two of the Treatment Card may be one color to match the mild barand the one background color, weeks three and four may be a differentcolor to match the intermediate bar, and weeks five and six may be athird background color to match the maximum bar.

Another option may be to have colors, letters or numbers (for example1.0, 2.0, 3.0, etc.) for the strengths of the kits where a dilution wasnot involved (for example cream or lotion that does not require mixingfrom a powder). In such a case, the patient Treatment Card backgroundcolors may correspond to the strength or color of the kit, rather thanan individual dilution or compound of the kit. In such a case the creammay be in separate packages outside the kit, but still color coded.Likewise, different color bars may be used to indicate the duration ofthe treatment in minutes, or the treatment parameters to be used on theultrasound or laser. Colors may be also used in color code to link or"intertwine" ultrasound/topical treatments and light or laser lighttreatments into a predetermined sequence and at the appropriate timeinterval.

In a preferred embodiment of the invention, for example, Step One of thekit may include the following items:

A tear and wipe prepackaged skin pad impregnated with a skin cleanser.

A sterile unpreserved unit dose package, vial, twist off plastic, tearpacket, etc. type of container which contains a solution that adjuststhe pH of the skin to pH 8.5

A vial of dry enzyme powder (which requires pH 8.5 to properlyfunction).

A small vial of an appropriate amount of sterile distilled unpreservedH₂ O to add to the dry powder.

A small plastic cup and plastic spatula to mix these in.

All of the items in Step One of the kit may be coded with the sameidentifying number, letter and/or color.

Step Two of the kit may include a set of instructions to use thecoupling gel and ultrasound as per the patient Treatment Cardparameters.

Step Three may include the active agent itself, in a sterile single usepackage, with any additional ancillary items needed for that particularagent.

Step 4 may include the post treatment skin protective regimen which mayinclude the following:

A cleansing agent to remove the specific active agent prepackaged.

A buffering solution to restore the skin to pH 5.5 (if necessary for agiven process or active agent).

An environmental protection lotion which may be specially formulated tohelp protect the skin until it has regained its own barrier function.

A possible nonirritating sun block to use on top of the environmentalprotective cream.

The present invention has numerous potential beneficial uses. Forexample, the present invention, in a preferred embodiment, may be usedto directly or indirectly produce beneficial effects by biochemicalstimulation of tissue or cells (or thermal events without the use oftopical agents) including such activities as stimulating fibroblastproduction of new collagen or elastic fibers. The present invention, ina preferred embodiment, may be used to lighten uneven or extra pigment(including melanin) in the epidermis or dermis. The present inventionmay be used to add, augment or supplement antioxidants, vitamins,phytonutrients, trace elements, minerals, or naturally occurring,synthetic or generically engineered substances which may alter orimprove the structure, health or function of the skin or subcutaneoustissue.

The present invention, in a preferred embodiment, may be used to:deliver agents which enhance, speed or promote wound healing; deliveranesthetic agents to the skin and subcutaneous tissues; improve skintone and "tighten" loose skin; to reduce the appearance of cellulite;reduce wrinkles or scars; deliver drugs for the purpose of producing anon-local, systemic effect (such as insulin); deliver agents in theirpure or neat form of in vehicles such as gels, creams, ointments,emulsions, micropolymer beads (or sponges, etc.), liposomes or othernatural or synthetic "transport device" used with or without a couplingmedia.

The present invention provides the possibility for the non-surgicalrejuvenation of skin, improved wound healing, better anesthetic forcutaneous surgery without needles, delivery of drugs that currently areineffective or poorly tolerated by topical delivery.

The presently disclosed embodiments are to be considered in all respectsas illustrative and not restrictive, the scope of the invention beingindicated by the appended claims, rather than the foregoing description,and all changes which come within the meaning and range of equivalencyof the claims are therefore intended to be embraced therein.

What is claimed is:
 1. A method for enhancing the transport of an activeagent through mammalian skin, comprising:exposing the skin toultrasound, and applying an active agent to the skin, wherein the stepof applying an active agent to the skin comprises injecting the activeagent into the skin.
 2. The method of claim 1, wherein the active agentcomprises human fibroblasts.
 3. The method of claim 1, wherein theactive agent comprises a preparation containing human fibroblasts.
 4. Amethod for enhancing the transport of an active agent through mammalianskin, wherein the skin comprises a stratum corneum, the methodcomprising:exposing the skin to ultrasound, applying an active agent tothe skin, and modifying at least portion of the stratum corneumsubstantially prior to the step of exposing the skin to ultrasound,wherein the step of modifying at least a portion of the stratum corneumcomprises at least one of the steps of: removing at least a follicularplug from the stratum corneum, removing at least skin debris from thestratum corneum, and removing at least a portion of the stratum corneum.